class Contain extends React.Component{
    render(){
        return <main>
                    <Goods></Goods>
                    <Order></Order>
                    <Saler></Saler>
                </main>
    }
}
/* Goods */ 
        class Goods extends React.Component{
            render(){
                return <div id="goods">
                        </div>
            }
        }
/* Order */
        class Order extends React.Component{
            render(){
                return <div id="order">
                        </div>
            }
        }
/* Saler */
        class Saler extends React.Component{
            render(){
                return <div id='saler'>
                        </div>
            }
        }
ReactDOM.render(
    <Contain></Contain>,
    document.getElementById('box')
)